A 50-year-old man underwent heart transplantation for low outputheart failure that was unresponsive to medical treatment. The affected heart at autopsy is shown in the image. It weighs 950 g (normal up to 350 g) and shows no evidence of coronary artery atherosclerosis. Histologically, the myocardium demonstrates hypertrophic myocytes and foci of myocardial fibrosis but no evidence of inflammation or myofiberdisarray. Which of the following is the most likely diagnosis?
Answer : B Dilated cardiomyopathy
Dilated cardiomyopathy (DCM) is the most common type of
of cardiomyopathy and is characterized by biventricular dilation, impaired contractility, and eventually congestive heart failure.
In the majority of cases, the cause is unknown (idiopathic DCM), although genetic factors often play a role.
The disorder can also develop in response to a large number of insults that may directly affect the myocardium (secondary DCM), including alcohol,cytotoxic drugs, and viral infections.
The heart is typically enlarged, often to remarkable proportions (“cor bovinum”). Hypertrophic cardiomyopathy displays myofiber disarray. The other choices do not lead to biventricular dilation and hypertrophy.